The present invention concerns an automatic selective device for sorting objects which differ in physical characteristics such as shape, type, consistency, weight, dimension, and/or volume and for placing these objects in suitable receiving containers, comprising a means for loading the objects, a means for transporting the objects to said receiving containers, and an unloading means for selectively depositing the objects into the receiving containers, wherein said transporting means and said unloading means are combined and comprise a unit of individual supports, each affixed to at least one endless conveyor (15), each support comprising a pivoting tray which receives the object to be sorted and having a front rim and a rear rim defined relative to the direction in which the support is displaced, as well as a device (22) which activates said pivoting tray, said activating device being controlled by an individual control device which, at a predetermined instant, pivots the tray in combination with gravitational force in correspondence with one of said receiving containers (30) selected as a function of the physical characteristics and/or the destination of the object transported by said tray.
Devices of this type operating on the basis of various principles are already known in the art. According to one such principle, the objects are transported on trays displaced along the receiving containers in the form of bags or bins and the objects pivot to the side when they reach their destination, then slide off. This method of operation requires the transported object to fall for quite some distance in relation to its size.
According to another operating principle, the tray remains horizontal and when the object reaches its predetermined destination, an electrically driven transverse belt ejects the object laterally. Here again, a considerable distance is required for the object to fall and more importantly, the trajectory of the object is uncertain, as it depends upon the relationship between the weight of the object and its volume.
In other systems, objects fall due to simple gravitational force, and in some cases they are ejected from containers with a movable base that opens automatically when the container passes over the container for which the object is destined.
Yet other systems use gripping devices which grasp the object, hold it while it is being transported, and open at the appropriate time as the object passes over the container for which it is destined.
U.S. Pat. No. 4,318,807 describes another type of device designed to sort beams transported by a moving belt and to deposit the beams in different compartments. To perform these operations, the transporting elements are formed of strong, U-shaped hooks articulated to the end of a rod integral with a guide rail. Due to the design of these elements, this device can only be used for moving large, heavy, compact objects.
The sorting device which is the subject of Japanese Patent Application No. 59 036020 is designed to sort fruit by weight. It has small cups for this purpose which are pivotably attached to an upright metal piece so they can rotate. The cups are locked in horizontal position by a locking system consisting of a lever cooperating with a stop located on the cup. When the device tips, the lever disconnects from the stop and releases the cup.
Prior art devices, in particular those described above, have various disadvantages. The controls that open the gripping devices or containers in certain cases, or which engage the pivoting motion in other cases, are computer driven and executed by activators, electromagnets, pneumatic cylinders, motors, etc. This results in complex, costly devices which do not fully respond to speed and efficiency requirements of sorting objects which vary considerably from one another in size, shape, type, and consistency, such as, for example, heavy packages weighing several kilograms, large but lightweight packages, very lightweight, flexible envelopes weighing several tens of grams, or cylindrical products such as beverage cans that are placed in an unstable manner inside a flexible pouch. Obviously, other types of situations may arise as well.
The object of the present invention is to overcome these disadvantages with an automatic selective sorting device for simultaneously transporting objects which differ in shape, type, consistency, weight, dimension, and/or volume and placing these objects in receiving containers which may have been preselected by means of a rapid, effective, simple and economical device.
This goal is achieved by a device such as the one described in the preamble, characterized in that said loading means comprises at least one storage and unloading buffer system, each equipped with at least one window designed to set an object on an acceleration belt, and one automatic insertion belt located downstream from the acceleration belt to deposit the objects on the pivoting trays of the individual supports that are located near at the rear edges of these trays, in that each individual support for said combined transporting and unloading means comprises a pivoting means to allow the tray to pivot from front to back relative to directions in which the individual supports are displaced, and in that the pivoting tray for each support overlaps the conveyor.
According to a preferred embodiment, the device comprises at least one guide rail for the individual supports and one guide element associated with each individual support which prevents said individual support from falling off the trajectory defined by the endless belt.
According to an interesting embodiment, the activating device comprises a coil spring designed to release enough energy to cause the pivoting plate to pivot, said coil spring being attached to an axle, having one end connected to said pivoting tray and one end connected to a fixed element on the individual support.
This activating device may comprise a disc-shaped cam with a peripheral notch which cooperates with a release to make the cam pivot and release the energy in the coil spring.
Said release preferably comprises an angled lever pivoting on an axle and holding two wheels located at each of its extremities, respectively, said wheels respectively cooperating with a device that controls the pivoting of the pivoting trays and with the cam.
Said angled lever is advantageously pushed into the stopped position by a spring.
According to one variation, the activating device may comprise a locking/unlocking mechanism that slides longitudinally and which is integral with the individual support, and which also may cooperate with a stop, integral with the pivoting tray, said locking/unlocking element being activated by an activating finger that pivots on an axis and is activated by a movable block integral with the frame of the device.
According to a first embodiment, each of said individual supports consists of a swing tray comprising a hook support attached to the conveyor and a suspension arm attached at one end to the hook support, and comprising at the other end, the pivoting tray which is attached in such a way that it remains inclined toward the front while objects are being transported.
In a particularly advantageous manner, the suspension arm of each swing tray is inclined from the vertical and it is angled in such a way that the center of gravity of the pivoting tray is located essentially on the vertical from the suspension point of the arm of the hook support.
According to a second embodiment, each of said individual supports consists of a pivoting tray attached directly to the conveyor.
In general, the pivoting tray comprises a surface for receiving objects defined in the front by a rectangular vertical rim and on each of its lateral sides by a triangular vertical rim, with the rear edge of the tray being open.
Advantageously, the receiving surface of the pivoting trays may be perforated.
According to another embodiment, the pivoting tray may comprise a moving belt located on the surface which receives the objects, said belt operating in a loop driven by two parallel rollers located near the front edge and near the rear edge of the tray, respectively.
Advantageously, the roller located at the front of the tray comprises a means which causes it to rotate when said tray pivots in order to active movement of the belt.
Advantageously, the means for driving the front roller comprises a friction drive wheel attached to the rotational axis of said roller and cooperating with a rail parallel to the guide rail for the individual supports when the pivoting tray pivots.
Since the trays pivots from front to back, the belt moves in the opposite direction to the direction in which the pivoting tray pivots.
The acceleration belt for the loading means moves faster than the displacement speed of the individual supports on the transporting means.
In the preferred embodiment of the device, when objects are transferred from the loading means to the transporting means, the automatic insertion belt is located in the extension of the pivoting tray while the objects are being deposited and it overlaps the rear edge of said tray while the objects are being transferred.
Said means for locating the objects onto the pivoting trays may advantageously comprise a manual insertion belt located upstream of the acceleration belt.
Advantageously, the at least one window in the storage and unloading buffer system comprises two movable armatures holding, at one free extremity, the free end of a retractable lateral curtain, said armatures being connected to two activators, while the other end of the retractable lateral curtain is connected to a spring roller and the activators preferably are pneumatic cylinders.